Christopher M. Fuhrmann,Christopher M. Fuhrmann, Ross P. Connolly, Charles E. Konrad IIRoss P. Connolly, Charles E. Konrad II

NOAA-Southeast Regional Climate CenterNOAA-Southeast Regional Climate CenterGeography DepartmentGeography Department

University of North Carolina at Chapel HillUniversity of North Carolina at Chapel Hill

Carolinas-Virginia Conference, NWS-Wilmington Office, 20 October 2009Carolinas-Virginia Conference, NWS-Wilmington Office, 20 October 2009

Winter Storms: An Overlooked Source of Death, Destruction, Winter Storms: An Overlooked Source of Death, Destruction, and Inconvenience in the Carolina Piedmont Regionand Inconvenience in the Carolina Piedmont Region

Insured losses from winter storms by climate district, 1949-2003

(Changnon, S.A., 2007: Catastrophic winter storms: An escalating problem. Climatic Change, 84, 131-139, Figure 4)

Objectives of this presentation:

• Provide an overview of the range of societal impacts associated with different types and intensities of winter storms at two locations within the Carolina Piedmont region

• Provide examples of how minor winter storms (meteorologically speaking) result in significant societal impacts

• Put forth recommendations for future work and follow-up studies

Study Area: The Carolina PiedmontRaleigh-Durham, NC (RDU) and Greenville-Spartanburg, SC (GSP)

RDU (n = 35) GSP (n = 32)

Blue = bottom quartile*

Red = top quartile*

A good representation of light moderate, and heavy events

A good representation of ice storms, snow storms, and winter storms

Winter Storms at RDU and GSP from 1995-2007

Utilized Storm Data entries and online newspaper databases:- Raleigh News & Observer, Durham Herald Sun, Spartanburg Herald Sun

Began searching the archives 3 days before the event and ended when no mention of the storm or its impacts for at least 2 consecutive days

Winter Storm

Meteorology

Social/Individual Factors

Utilities

BusinessCommerce

IndustryTransportation

School ClosingsDelays

DeathsInjuries

EmergencyManagementGovernment

PerceptionsDecisions

Climatology

PropertyDamage

Insured Losses

School Closings and Delays

• A high percentage (78%) of storms examined in this study affected public (K-12) school schedules

• Most cancelations lasted one day, but there were notable exceptions

• According to newspaper reports in the RDU area, colleges and universities were more likely to remain in session or cancel only early morning classes, even if K-12 schools had already canceled

• Public transportation

• Numerous reports of university classes being held despite hazardous driving conditions and power outages

1

9 6

4

3

2

578

One of the more intriguing results was the difference in perceived coordination among school districts between RDU and GSP

Spartanburg Co. School Districts

• 5 Feb 1996: Districts 1 and 2 operate on a 1-hour delay; District 3 operates on a 2-hour delay; remaining districts operate normally

• 16 Feb 1996: Districts 1 and 2 cancel classes at 9am; District 3 cancels at 9:30am; remaining districts cancel by 11am “to avoid confusion”

• 5 Jan 1999: Districts 1, 2, 3, and 7 operate on a 2-hour delay; remaining districts operate normally

• 26 Jan 2004: Districts 3 and 4 operate on a 2-hour delay; District 6 operates on a 1-hour delay; remaining districts operate normally

Impacts on Utilities

• Accurate information on power outages is extremely difficult to obtain through newspaper and Storm Data records

• Newspaper reports typically cited felled trees on electrical wires as the cause of most power outages

• Issues to consider: trees that are predisposed to damage; prevention/mitigation through aggressive tree “trimming”

The power is restored

Power companies are NOT responsible for repairing

weatherheads and insulators, which are often damaged when

power lines fall

From Call, D.A., 2007: An analysis of ice storm impacts, warnings, and emergency management response. Doctoral Dissertation, Department of Geography, Syracuse University (Figure 2.5)

…….or is it?

Impacts on Transportation

• NC Highway Patrol: call volume over a 24-hr period can more than double during a winter storm compared to a normal 24-hr period

• Most accident calls made during and immediately after the period when precipitation is heaviest (often during the early stages of a storm)

• Different types of roadways are impacted in different ways by winter storms

• Highways and Interstates

• Major arterial/connector roads

• Secondary/local roads and bridges

• Temperature is critical

• How effective is pre-treatment?

Deaths Due to Winter Storms

n = 43

Under What Circumstances Do Minor Events Have Significant Societal Impacts?

• Three unique events are highlighted in this presentation:

• “Bad Timing” 29-30 January 1995 (< 0.1” of freezing rain and sleet at RDU)

• “Gridlock Wednesday” 19 January 2005 (~1” of snow at RDU)

• “Frozen Peaches” 9-10 March 1999 (2-3” of wintry mix at GSP)

“Bad Timing”

• Forecast: mostly rain throughout the day on the 29th and early morning of the 30th; brief transition to FZRA and sleet expected late-morning (10-11 LST); only trace amounts on cold ground; otherwise little accumulation expected due to warm surface temperatures

• NWS Raleigh issues Winter Storm Advisory; In response, Wake County filled over a dozen trucks with salt and sand

• What happened: Freezing precipitation began earlier than expected, at the height of the morning rush (07-09 LST); traffic already on the roads made it difficult for trucks to treat them

• Impacts: Nearly 100 accidents in the RDU area on major roadways and highways; two were fatal; accidents and congested roadways forced many businesses, government offices, and some school systems to close

“Gridlock Wednesday”

• A quick burst of snowfall in the RDU area lead to the early release of businesses and schools around mid-day on 19 January; however, A combination of human and meteorological factors turned this minor event into an infamous one

• Quick burst of snow + very cold surface and air temperature = large, dry snowflakes

• Simultaneous closure of business and schools = “Super Rush” (Call 2007)

• Even with gridlock on the roads, a large number of accidents (some serious) were reported due to cars skidding and sliding

• Theory posed by the NWS Raleigh Office:• Snowflakes partially melt due to heat released

from automobile exhaust• The resulting slush became compacted from

slow-moving traffic• Cold ground and air temperatures caused

compacted slush to freeze into thin layer of ice

“Frozen Peaches”

• Light snow began falling in the SC Upstate in the early morning hours of 9 March 1999, transitioning to a wintry mix which lasted until late-morning

• Closure of schools made it one of the latest snow days in recent memory

• One of the biggest concerns with this event – the budding peach crop

• Early March – peach crop transitions from tight bud to breaking bud (susceptible to damage from cold temperatures and freezing precipitation)

• Delay in planting in late fall 1998 prevented major damage (potential to cost millions!)

Recommendations and Future Work

• Determine how municipalities (as well as rural communities) can better prepare for and respond to winter storms

• Determine if the policies currently in place are sufficient in handling school closings and delays in a safe and efficient manner

• Assess the effectiveness of chemical solutions currently used to treat roadways

• Assess whether media coverage of roadway treatment before an event is providing motorists with a false sense of security

• Assess whether media outlets are providing sufficient warning of the dangers of carbon monoxide poisoning, as well as other environmental hazards

• Assess how communication between power companies and customers can be improved; are power companies relaying accurate information to their customers?

• Assess whether aggressive tree-trimming helps in mitigating the number and duration of power outages